Cortical folding in the continuum of psychosis: a meta-analysis using coordinates, T-maps, and individual raw data

Description: Schizophrenia is thought to result from abnormal neurodevelopmental processes including alterations during the perinatal period that may have lifelong impacts on brain surface morphology and cortical folding. Many researches have focused on finding the stigmata of these early neurodevelopmental brain alterations and thus have examined gyrification in patients with schizophrenia and across the continuum of psychosis with mixed results. Here, we aimed to determine whether gyrification abnormalities were present along the psychosis continuum by conducting a systematic review and meta-analysis of studies investigating Local Gyrification Index (LGI) in patients with schizophrenia, patients with a first-episode of psychosis (FEP) and individuals with a high clinical and/or genetic risk for psychosis. Twenty-one studies were included in the meta-analysis and were pooled with two large-scale public databases for a total of 1004 patients with schizophrenia, 317 FEP, 401 at-risk individuals, and 1299 healthy controls. Whole-brain meta-analyses of LGI findings were conducted with the Seed-based d Mapping (SDM) software on T-maps and coordinates from processed and raw data. Then, frequentist and Bayesian meta-analyses were carried out on 5 bilateral regions-of-interest (ROI). Finally, meta-regressions and linear regressions from raw data processing were used to examine the effects of clinical and demographic variables on LGI differences. We found no difference in LGI between groups in either our whole-brain or ROI meta-analyses. In addition, the Bayesian ROI meta-analysis showed strong evidence for no difference. At the study level and at the individual level, our analyses revealed no significant association between LGI and clinical and demographic variables. Further studies are needed to determine the most appropriate method for measuring cortical folding in the schizophrenia spectrum and to clarify the effect of potential confounding variables. This repository includes the unthresholded statistical maps from 3 comparisons: patients with schizophrenia vs. healthy controls, individuals with first-episode psychosis vs. healthy controls, individuals with an at-risk state for schizophrenia vs. healthy controls.